The goal of the proposed program is to address several technical feasibility questions (in Phase I), and then demonstrate (in a subsequent Phase II) a safe, compact patch-like monitoring device for directly measuring blood flow to the brain in very low birth weight (VLBW, <1500gm) infants. In Phase I, the accuracy of 3D Doppler techniques will be evaluated for the vessel sizes and geometries specific to the neonatal brain, and the feasibility will be determined for implementing these techniques using a compact MEMS-based ultrasound transducer module. In Phase II, a full-scale transducer prototype will be developed and demonstrated in animal and/or clinical studies. Finally, in Phase III the monitoring hardware and software will be commercialized and translated to the clinical market, likely in partnership with manufacturers of existing neonatal monitoring equipment. The clinical market stands to benefit greatly from this innovation, given that nearly 64,000 VLBW infants are born in the U.S. each year. Many of these fragile patients will sustain devastating brain injuries during the first days and weeks of life due to abnormal blood flow to the brain. Currently, brain injuries cause 5-10% of VLBW survivors to suffer from cerebral palsy and many more will develop cognitive or behavioral abnormalities in later life. Regular monitoring of blood flow to the neonatal brain would provide physicians the information needed to intervene early, reducing the likelihood of lasting injury. This would clearly have immense human benefit and would also reduce healthcare spending, given recent estimates that suggest the lifetime cost of care for each cerebral palsy patient will exceed $1M.